From the White Wolf Wiki, the most complete White Wolf reference

A rite is a gift from spirits given to a Garou which allows them to exert their own will onto the world to do something beyond their normal abilities

These rites may be as simple as the Get of Fenris gathering for departed, in which they perform a special funeral where the body is burned along with the deceased's possessions; during the rite, the Get ask the Valkyries to speed them to the afterlife. More complicated are rites such as as the Rite of Caern Building in which an army of Garou attempt to create a sacred wellspring of Gnosis while the Wyrm's agents send wave after wave of enemies against them.

[edit] List of Rites